Common cell phone signal jammers are used to shield cell phone signals by emitting interference signals. By transmitting a high-power signal of a certain frequency, the surrounding electromagnetic environment is severely damaged, and the cell phone cannot normally obtain and analyze the signal from the base station, thereby achieving the purpose of shielding the cell phone signal.
Under normal circumstances, when a cell phone enters a cell for the first time, the local cell base station will update and manage the location of the cell phone, and at the same time allocate temporary user information such as a new temporary mobile user identifier to it. So as to determine the location of the community where you are. When the cell phone signal jammer is working, it sends out an interference signal, which interferes with the effective signal on the base station broadcast channel frequency band. The interference signal increases the bit error rate of the mobile communication channel and reduces the signal-to-noise ratio of the channel, thus affecting the cell phone Effective reception of base station broadcast information, when the signal-to-noise ratio is reduced to a certain extent. The cell phone cannot normally decode the broadcast information of the base station, thus losing contact with the base station. The cell phone cannot determine the service area where it is located many times, so the cell phone in the interference area shows no signal and is not in the service area.
The second is the pseudo base station mode. When the cell phone jammer operates, the user’s cell phone signal can be forced to connect to the device, so that it cannot be connected to the public mobile communication network.
There are also some new cell phone signal jammers that use other principles to interfere with cell phone signals, such as pilot signal interference.